Q: How to link a pdf file in ePub 3? i'm developing an ePub using Sigil.
I have addedd some PDF file in my Misc Folder.
Now i've created a link to that file, and everything is working fine with iBooks on my Mac.
But on iBooks for iOS7 when i tap the link it load (in overlay) a gray page, is this a bug?
Should i use another way for link the PDF?
Thanks.

A: This is probably an issue with iBooks for mac not really requiring strict ePub code. Many times things that "work" in iBooks for mac aren't actually compliant at all. I can't speak for Sigil directly, but can help with the ePub itself: I am guessing you need to change some things in your .opf file: you need to include the pdf as an item in your manifest AND as a nonlinear page in your spine: , . 
You should use ePubcheck (https://github.com/IDPF/epubcheck) to make sure you are exporting a valid ePub.
If you need a tool to zip/unzip your ePub I would use this: http://www.mobileread.com/forums/showthread.php?t=55681
Good luck!
